The present invention relates to a golf club, more particularly to a head for a golf club called an iron.
To replace a conventional golf club head made of a metal core and a fiber-reinforced resin coating the core, a golf club head whose hosel and sole are integrally formed of a metal and which has a filling member made of a synthetic resin and disposed on the sole and has a fiber-reinforced resin coating the hosel and the filling member has recently been proposed as a head which can be designed to have its center of gravity low enough to be properly handled by a beginner golfer or an unpowerful golfer and are softer in the feeling of hitting of a golf ball and better in the length and direction of hitting-away of the ball than the conventional head, as disclosed in Japanese Utility Model Applications (OPI) No. 154968/86 and Japanese Patent Application (OPI) No. 5767/88 (the term "OPI" as used herein means an "unexamined published application").
In such a head disclosed in the Japanese Utility Model Application (OPI) No. 154968/86, a hosel and a sole are integrally formed of a metal such as soft iron and stainless steel, and a filling member is made of a fiber-reinforced resin and a heavy material mixed therewith and has a nearly triangular cross section. The filling member is integrally coated with a fiber-reinforced resin layer whose cross section is shaped nearly as inverted V and whose lower portion has a flat front surface nearly flush with that of the upper portion of the sole.
In such a head disclosed in the Japan Utility Model Application (OPI) No. 5767/88, a sole made of a metal, a core made of a light synthetic resin of 0.6 or less in specific gravity, and a body which is made of a synthetic resin and reinforcing fibers mixed therewith and coats the core are integrally formed together.
In each of the heads disclosed in these Applications, the filling member is supported at the bottom thereof by a projection extending slightly up from the sole, and entirely differs in material from the sole. For that reason, it is likely that the filling member is tilted rearward and separates from the sole at the time of hitting of a golf ball with the head, namely, the head is damaged at that time. This is a problem. If the projection were made taller to more securely support the filling member, the center of gravity of the head would be elevated to make it difficult to properly handle the golf club. This is also a problem.